The present invention relates generally to seals, and more particularly to multilayer, extruded seals having a wider temperature stability range and a lower compression set resistance, and to a method for the manufacture of such seals as well as to the use of such seals between an automotive engine the air intake manifold.
In recent years there have been numerous restrictions and regulations imposed upon manufacturing industries in general and particularly upon automotive manufacturers, which are intended to reduce the amount of potentially harmful contaminates from being released into the environment by such industries. In the automotive industry, such regulations and restrictions severely limit the amount of hydrocarbon fuel vapor and other chemical materials that can permeate from of motor vehicles. The regulations and restrictions have a dramatic impact on the manufacture and use of polymeric and rubber components such as seal members used in the automotive industry. Typically, the various seals employed in the automotive industry are molded and are composed of fluoroelastomer rubber materials. However, these molded fluoroelastomer seals are relatively expensive to manufacture due, in part, to the slow production cycling time and, in part, to the expensive tooling required for the manufacture of such molded seals. Furthermore, such molded seals are prone to excess parting line flash, which can lead to a separate operation to remove the parting flash from each individual seal. In some instances the parting flash may be severe enough to lead to total rejection of the seals.
Accordingly, there is a need in the automotive industry for an improved seal member for use in automotive industry as a seal member between the air intake manifold and the automotive engine, which not only meets industry standards for fuel emission, but also is able to perform well over a wide temperature range and, at the same time, exhibit a low compression set resistance; and for a method for manufacturing such automotive seals which overcomes the high costs and manufacturing problems associated with the manufacture of prior seals.